A problem occurs in TEX and LATEX when you try to align columns in a table on
the decimal point (or any other character).   There is now a document style
option in LATEX called `decalign', which adds a new column specifier to the
tabular and array environments.  Use a `d' to indicate that a column should
contain entries aligned on the decimal point.  An optional character after the
`d' indicates the character to be used as the separator; the default is a
period.  To use this option simply put :
   \documentstyle[decalign]{report}    <---- decalign in the document style

Use a `d' to indicate that a column should contain entries aligned on the
decimal point.  An optional character after the d indicates the character to be
used as the separator; the default is a period, but Europeans will probably use
commas. 

To align along the decimal point in plain TeX, define two columns in the
template like this:
  &\catcode`.=4 \tabskip0pt \hfil#&.#\hfil\tabskip=<whatever> &

                                 Stephen Meatheringham